There is a method of automatically generating a program code such as a source code based on a program specification generated in advance. For example, there is a method of generating a program code from a block diagram. The block diagram is constituted by a plurality of blocks and a connection line connecting the blocks to one another. In each block, elements of a data processing procedure are defined. Specifically, a group of data processes are defined in each block. In the block diagram, by connecting the blocks to one another by the connection line, there is described a flow of the data processing procedure in a program from acquiring an input value until outputting an output value indicating a calculation result.
As a technique of generating a program code from a block diagram, for example, there is a technique disclosed in Patent Literature 1.